This book describes and summarizes the radiation responses of both normal and neoplastic tissues with a focus on rational strategies for the modification of these responses. Emerging data from molecular oncology and radiobiology that form the basis for a better understanding of radiation-induced reactions and key features of malignant growth are reviewed in depth. The book covers not only general principles of radiation-induced reactions but also a large number of preclinical and clinical data that will guide the reader through this complex and dynamic field and will provide valuable information for the development of further research projects. Many of the data reviewed in this book form a sound basis for further improvement of state-of-the art radiation therapy by integrating biological information into the process of treatment planning and delivery.